Secondary organophosphine sulfides and the preparation thereof



3,159,667 SECONDARY ORGANQPHOSPHINE SULFIDES AND THE PREPARATION THEREOF Grace A. Peters, Stamford, Conn, assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine N Drawing. Filed Dec. 2, 1959, Ser. No. 856,665

7 Claims. (Cl. 260-481) The present invention relates to new and useful organephosphorus compounds and to the preparation thereof. More particularly, the instant discovery concerns"second ary phosphine sulfides.

The secondary phosphine sulfides herein contemplated correspond to the general formula i X-H wherein X is a member selected from the group consisting of where Ra and Rb, respectively, represent substituted and unsubstituted, branched and straight chain saturated alkyl radicals, in which any given linear carbon chain of said radicals contains from 1 to 18 carbon atoms; substituted and unsubstituted aryl radicals; substituted and unsubstituted saturated alicyclic radicals; and Ra and Rb, respectively, are attached directly to the phosphorus atom through a carbon atom. Ra and Rb may be the same or different radicals.

R to R in the above formula represent alkyl chains of "ice wherein Ra and Rb arethe same as above.

The 2,4,6 trisecondaryalkyl 1,3 -dioxa 5 phosphacyclohexanes contemplated herein are prepared as described in copending U.S. application Serial No..766,656, filed October '13, 1958, now U.S. Patent No. 2,984,683, which is incorporated herein by reference. The 2,4,6-triisopropyl 1,3 dioxa 5; phosphacyclohexane referred to above, for example, is prepared as shown in Example A, infra.

Typical secondary phosphines within the purview of the instant invention are: diphenylphosphine; bis(4 chloro phenyl)phosphine; dibutylphosphine; didodecylphosphine; bis(2 phenylethyl)phosphine; dicyclohexylphosphine; bis(3 ethylhexyl)phosphine; bis(2,4,4 trimethylpentyl)phosphine; bis(3 chloropropy1)phosphine. bis(2- butenyl)phosphine; ethylhexylphospln'ne; dioctylphosphine; diisooctylphosphine; bis(3 methoxycyclohexyl)- phosphine; bis(3 ethoxycyclopentenyl)phosphine; 2,4,6

l to 10 carbon atoms and, as will be seen hereinafter, R

R R R R and R may be the same or different radicals. According to the present inventionsecondary phosphines corresponding to the groups just defined are reacted with one molar equivalent of sulfur and in the presence of the inert organic solvent, such as benzene, to produce the corresponding secondary phosphine sulfide. Reactions of this type are carried out, according to the present invention, in an inert atmosphere, i.e., a non-oxidative at mosphere, such as in the presence of nitrogen, hydrogen, CO and the like, and at temperatures in the range of 0 C. to 100 C., preferably 15 C. to 75 C. Preferably,

the temperature employed is below the boiling point of the solvent employed.

For instance, 2,4,6-triisopropyl-1,3-dioxa-5-phosphacyclohexane is reacted as follows with sulfur under nitrogen and in the presence of benzene to produce 2,4,6 triisopropyl 1,3 dioxa 5 phosphacyclohexane-S-sulfide2 Among the numerous secondary phosphines suitable for the present invention are the compounds corresponding to the formula tris(3 heptyl) L 1,3 dioxa 5 phosphacyclohexane; 2- (3 hexyl) 4,6 diisopropyl 1,3 dioxa 5 phosphacyclohexane; bis(2 phenoxyethyl)phosphine; bis(2 aminoethyl) phosphine; bis (2 nitropropyl phosphine; bis- (2 sulfoethyl)phosphine; bis(carbamylmethyl)phosphine; bis (2 ureidoet-hyl phosphine; bis(hydr0xymethyl) phosphine; bis(1 hydroxyhexyl)phosphine; bis(3 carboxypropyl)phosphine; bis(3 carbethoxypropyl)phosphine; bis(4 aminophenyhphosphine; bis[2(4 aminophenyl)ethyl] phosphine; and the like; and mixtures thereof, such as a reactant mixture of dioctylphosphine and diisooctylphospbine, and similar mixtures.

The inert organic solvents contemplated herein, i,e inert with respect to the reactants and the reaction products under the conditions of the reaction, are numerous. Typical among these are hydrocarbon and chlorinated hydrocarbon solvents, such as benzene, toluene, xylene, hexane, heptane, chloroform, carbon tetrachloride, dichloroethane, perchloroethylene, methylene dichloride, and the like.

While atmospheric pressures are desirable for reaction of the secondary phosphines with sulfur, superand subatmospheric pressures are suitable. The reactants contemplated herein are generally present in stoichiometric quantities, i.e., in substantially equimolar amounts, although an excess of the secondary phosphine 2,4,6-Triis0pr0pyl-1,3-Dioxa-5-Phosphacycloherane A one liter, three-necked reactor flask is equipped with a gas inlet tube, an addition funnel, a mechanical stirrer and a gas bubbler device so disposed that all exit gases from the flask pass upwardly therethrough, the bubbler device comprising a column containing a two-inch head of water. The reactor flask is charged with a solution mixture at ambient temperature (21 C.23 C.) of 200 milliliters of a concentrated aqueous solution of hydrochloric acid containing 37.7 percent HCl by weight and 200 milliliters of tetrahydrofuran.

Subsequently, the flask system and the charge are purged substantially free of oxygen-containing gas with nitrogen gas, and then a total of 108 grams (1.5 moles) of isobutyraldehyde and 17 grams (0.5 mole) of gaseous phosphosphines and solvents employed being given in the table phine, at ambient temperature (21 C.-23 C.), is slowly below; and continuously introduced into the charge over a period of 30 minutes.

A reaction mixture results which, after settling for 3 Example secondary Phosphme Solvent minutes, leaves an upper organic layer or phase which is separated from the remaining reaction mixture and dis- VI cyclohexyl z cyanocthylphosphme Cum tilled under reduced pressure. A total of 91 grams (78 VII -0cty1-2-cyanoethy1phosphine 06H, h f (1 t2 4 L1 D phenylphosphine C014 percent of t eory) 0 pro ac rnsopropy 1 Bis(2-cnl orophcnyl)phosphine omen S-phosphacyclohexane is thus collected as a colorless llqllld M thylos pr pyl)phosphine C01 having a boiling point of 100 C.101 C. at 8 millimeters pressure. The material has a pungent odor and a refractive index of n =1.4602. Analysis. Calculated for C H O P: C, 62.04; H, 10.85; P, 13.34. Found: C,

The present invention will best be understood by referin ea'ch example the Correspondmg Secondary Phosphlne ence to the following illustrative examples: Sulfide is recovered- As indicated above, the compounds of the present in- A L I vention are useful as fungicides and nematocides. The following tables illustrate this activity (all percentages Seventy cubic centimeters of benzene and 7.5 grams given as percent by weight): (0.05 mole) of di-n-butylphosphine are admixed. To the resulting solution 1.65 grams (0.05 mole) of powdered TABLE II sulfur is added under nitrogen. The resulting mixture is I stirred and allowed to stand overnight. Upon removing the benzene solvent di-n-butylphosphine sulfide is regigg 'ggfg Sdmtmia covered having the following analysis: Calculated for sulfide fructz'genta, C H PS: C, 53.9; H, 10.75; I, 17.4; S, 18.0. Found: C, ggf ggg gg f Pmmt 52.33; H, 10.41; P, 17.69; S, 18.0.

0.001 100 EXAMPLE II N l 1 t g A solution of 5.0 grams (0.033 mole) of dnsobutylphosmm m Damn a e phine in 50 cubic centimeters of benzene is prepared. To this solution 1.1 grams (0.033 mole) of powdered sulfur TABLE III is added under nitrogen and the resulting mixture thoroughly agitated. This mixture is allowed to stand overnight and then the solvent removed. A crystalline diisobutylphosphine sulfide is recovered having the following ma Anguilla 5 analysis: Calculated for C H PS: C, 53,89; H, 10.74; S, 40 l ggg ggg Percent kill1 17.99. Found: C, 53.89; H, 11.06; S. 18.29.

.1 EXAMPLE 111 N .1 t To a solution comprising 4.5 grams (0.0192 mole) of umerm Bergen age bis(2-carbethoxyethyl)phosphine in 60 cubic centimeters of benzene is added under nitrogen 0.62 gram (0.0192 Referring to Table 11, above, a water mixture of 0.001 mole) of powdered sulfur. The resulting mixture 1s agiercent di-n-butylphosphine sulfide produced according to tated and all w d t0 t Ovemlght- The solvent 15 the present invention is prepared and the spores admixed mtlJged and th 38 cg l l g f mg)12 21 53 therewith for a 20-hour period. After this period the 811 dB recovered Ana ysisa cu ate or 10 19 s ores are examined microsco icall o determ'n rcent C, 45.10; H, 7.19; P, 11.63. Found: C, 45.26; H, 7.19; gzrmination' p y L 1 6 P8 P, Referring to Table III, a Water mixture of 0.1 percent EXAMPLE IV 55 di-n-butylphosphine sulfide produced according to the present invention is prepared and nematodes admixed there- To a solution comprising 7.0 grams (0.03 mole) of with for a 20-hour period. Immediately thereafter per- 2,4,6-triisopropyl-l,3-dioxa-S-phosphaW o e i 75 cent mortality is recorded. cubic centimeters Of benZene 1S gram Obviously the ompounds of thg present invention 9 Of p Sulfur under nltmgen and f resultmg 0 manifest varying degrees of nematocidal and fungicidal mixture surf d a anOwed to d Ovemlght P activity and the above illustrations are merely typical. removal of the solvent the phosphine sulfide derivative Clearly the instant discovery encompasses numerous 15 recovere modifications within the skill of the art. Consequently, EXAMPLE V While the present invention has been described in detail with respect to specific embodiments thereof, it 1s not intended that these details be construed as limitations upon Example IV is repeated in every essential respect with the scope of the invention, except insofar as they appear the exception that 66 cubic centimeters of chloroform is substituted for the 75 cubic centimeters of benzene. As in in the appended claims. Example IV, the corresponding phosphine sulfide product 70 What is claimed is: is recovered. 1. Di-n-butyl phosphine sulfide. EXAMPLES VLXIV 2. Di-isobutylphosphine sulfide.

3. Bis(2-carbethoxyethyl)phosphine sulfide. Equimolar amounts of sulfur and a secondary phosphine P PY "p p are reacted essentially as shown in Example 1, above, the sulfide.

5. A secondary phosphine sulfide corresponding to the formula s H X-H 'whereinXrepresents HO-CH HCOH I R5 0 R2 CH 13 R4 R3 wherein Ra and Rb, respectively, represent a member selected from the group consisting of substituted and unsubstituted, branched and straight chain alkyl having from 2 to 18 carbon atoms, substituted and unsubstituted phenyl, substituted and unsubstituted cyclohexyl, substituted and unsubstituted cyclopentyl, said substituents for alkyl, phenyl, cyclohexyl and cyclopentyl being selected from the group consisting of lower alkoxy, halogen, phenoxy, amino, cyano, nitro, ureido, sulfo, hydroxy, carbamyl, carb(1ower)-alkoxy, carboxy, and phenyl; and Ra and Rb, respectively, are attached directly to the phosphorus atom through a carbon atom; Ra and Rb can'be the same and they can be different; R to R each represent alkyl hav- -.ing from 1 to 10 carbon atoms, and R R R R R and R need not be the same radicals; which comprises re acting equimolar amounts of sulfur and a secondary phos phine of the formula selected from the group consisting of wherein Ra, Rb, and R to R have the meanings given hereinabove; said reaction being made to take place at a temperature in the range of 0 C. to C. in an inert organic solvent and in an inert atmosphere; and recovering the resulting corresponding secondary phosphine sulfide.

7. A method according to claim 6 wherein the solvent is benzene.

References Cited by the Examiner UNITED STATES PATENTS 2,138,835 12/ 38 Butz 260606.5 2,274,291 2/42 Clayton et a1. 252-53 2,573,568 10/51 Hartman et al 25249.9 2,653,161 9/53 Ballard et a1. 260-461 2,856,369 10/58 Smith et a1. 260-2 OTHER REFERENCES Organophosphorus Compounds (Kosolapofi), pub. by John Wiley and Sons, Inc. (N.Y.), 1950, (pages 99 and 141). Also, pages 23 and 38-40, and page 31.

Malatesta: Gazz. Ohim. ItaL, 77, 509-511, 520-524 (1947). v LORRAINE A. WEINBERGER,

Acting Primary Examiner.

LEON ZITVER, TOBIAS E. LEVOW, ABRAHAM H. WINKELSTEIN, ROGER L. CAMPBELL, Examiners. 

3. BIS(2-CARBETHOXYETHYL)PHOSPHINE SULFIDE.
 6. A METHOD OF PREPARING A SECONDARY PHOSPHINE SULFIDE CORRESPONDING TO THE GENERAL FORMULA 